Vacuum cleaner and wet dust filter

Abstract

A vacuum cleaner ( 100 ) comprises a suction head ( 120 ), a suction source operable to generate suction at the suction head ( 120 ) for collecting dust or debris from a surface, a liquid filter assembly ( 190 ), and a handle portion ( 140 ) adapted to enable a user to move the suction head ( 120 ) on the surface during normal vacuuming operation. The liquid filter assembly ( 190 ) comprises an air inlet ( 1906 ) for receiving dusted air coming in from the suction head ( 120 ), a filter reservoir ( 1902 ) for receiving a cleansing liquid such as an aqueous cleansing liquid to form a cleansing bath for filtering dusted air coming in from the suction head ( 120 ), and an air outlet ( 1908 ) through which air moving out of the filter reservoir ( 1902 ). The liquid filter assembly ( 190 ) is mounted on a filter receptacle ( 186 ) formed on a rigid housing portion which is intermediate between the handle portion ( 140 ) and the section head ( 120 ).

The invention claimed is: 
     
       1. A dust filter comprising an air inlet, a liquid container comprising a bottom surface and a peripheral wall and defining a first reservoir for holding a cleansing liquid bath to facilitate liquid cleansing of dusted air and a second reservoir for receiving and storing cleansing liquid that moves away from said first reservoir in response to tilting of said dust filter, an inlet duct extending from the air inlet to inside the liquid bath, and an air outlet at a top end of the liquid container for liquid cleansed air to egress from said liquid bath; wherein the bottom surface of the liquid container cooperates with a first axial portion of the peripheral wall to define the first reservoir and the second reservoir is defined on a second axial portion of the peripheral wall which is above the first axial portion of the peripheral wall;
 wherein the peripheral wall flares or spreads outwardly on projecting upwardly away from the first reservoir and then converges to narrow as it extends towards the top end of the liquid container to define the second reservoir; and 
 wherein said air inlet, said air outlet and said air inlet duct collectively form a detachable assembly which is removable from a top end of said dust filter. 
 
     
     
       2. A dust filter according to  claim 1 , wherein the second reservoir is located between the air outlet and the first reservoir, and the volume of said second reservoir is comparable to or larger than that of said first reservoir such that cleansing liquid moving away from said first reservoir and towards said air outlet due to titling of said dust filter will be received by said second reservoir. 
     
     
       3. A dust filter according to  claim 2 , wherein said second reservoir comprises a concave receptacle which surrounds said inlet duct or two concave receptacle portions which are on diametric opposite sides of said inlet duct. 
     
     
       4. A dust filter according to  claim 1 , wherein the dust filter comprises a rigid housing on which said first reservoir and said second reservoir are defined, and the portion of said rigid housing that defines said second reservoir flares or gradually spreads outwards on extending concavely away from the first reservoir initially and then tapers or converges to narrow on extending concavely towards the top end of the liquid container to define a or said concave receptacle or a or said concave receptacle portion as it extends away from said first reservoir and in a direction towards said air outlet. 
     
     
       5. A dust filter according to  claim 1 , wherein said peripheral wall interconnecting said air outlet and said first reservoir defines said second reservoir, and said peripheral wall defines a curved volume which tapers towards said first reservoir to define said second reservoir. 
     
     
       6. A dust filter according to  claim 1 , wherein said first reservoir is at bottom, said air outlet is at top, and said second reservoir is intermediate said first reservoir and said air outlet; and wherein said second reservoir is formed as a continuation to said first reservoir to define a liquid receptacle which is at an inclination to that of said first reservoir. 
     
     
       7. A dust filter according to  claim 6 , wherein said inclination is larger than or equal to one of 15°, 30°, 45°, 60°, 75°, 90° and/or smaller than or equal to one of −15°, −30°, −45°, −60°, −75°, −90° relative to liquid surface of said first reservoir when said dust filter is not tilted. 
     
     
       8. A dust filter according to  claim 1 , wherein said air inlet is surrounded by said air outlet, and said air inlet duct is suspended on said rigid housing and extends in an axial direction downwards towards and into said first reservoir, said axial direction being orthogonal or substantially orthogonal to liquid surface of said first reservoir when said dust filter is not tilted. 
     
     
       9. A dust filter according to  claim 1 , wherein a baffle is formed on said air inlet duct at a level above the cleansing liquid level defined by said first reservoir to block upward splashing of cleansing liquid from said first reservoir towards said air outlet during normal vacuuming operation. 
     
     
       10. A dust filter according to  claim 9 , wherein an air outlet duct is provided to guide air egressed from said first reservoir to move to said air outlet, wherein said air outlet duct surrounds said air inlet duct, extends towards said first reservoir, stops at an elevation above said baffle and has an aperture shielded by said baffle. 
     
     
       11. A vacuum cleaner comprising a suction head, a suction generator operable to generate vacuuming suction at the suction head to take in dusted air, a handle portion adapted to move the suction head to work on a surface to be vacuumed, and a dust filter; wherein the dust filter is to operate at an elevation level above said surface and/or said suction head during normal vacuuming operation and said elevation changes in response to change in tilting of said handle portion relative to said surface and/or said suction head; and wherein said dust filter comprises a reservoir to define a cleansing liquid bath to facilitate cleansing of dusted air coming in from said suction head; wherein the dust filter comprises an air inlet, a liquid container comprising a bottom surface and a peripheral wall and defining a first reservoir for holding the cleansing liquid bath to facilitate liquid cleansing of dusted air and a second reservoir for receiving and storing cleansing liquid that moves away from said first reservoir in response to tilting of said dust filter, an inlet duct extending from the air inlet to inside the liquid bath, and an air outlet at a top end of the liquid container for liquid cleansed air to egress from said liquid bath; wherein the bottom surface of the liquid container cooperates with a first axial portion of the peripheral wall to define the first reservoir and the second reservoir is defined on a second axial portion of the peripheral wall which is above the first axial portion of the peripheral wall;
 wherein the peripheral wall flares or spreads outwardly on projecting upwardly away from the first reservoir and then converges to narrow as it extends towards the top end of the liquid container to define the second reservoir; 
 wherein said dust filter is mounted on a filter receptacle formed on a rigid and elongate housing portion that connects the handle portion to the suction head such that said dust filter follows movements of said handle portion during normal vacuuming operation, 
 wherein an assembly comprising said handle portion and said dust filter is moveable, for example pivotally moveable, relative to said suction head about a hinge axis or a universal joint, and 
 wherein said hinge axis being orthogonal or substantially orthogonal to a longitudinal axis extending along said elongate housing portion. 
 
     
     
       12. A vacuum cleaner according to  claim 11 , wherein said filter receptacle is adapted to detachably receive said dust filter, and said dust filter is to move towards said receptacle for attachment and move away from said receptacle for detachment in a direction orthogonal or substantially orthogonal to said longitudinal axis. 
     
     
       13. A vacuum cleaner according to  claim 12 , wherein said filter receptacle comprises a concavely curved back portion which is shaped for fitted reception of said dust filter; wherein said dust filter is formed as a plug-in module for plug-in coupling into the filter receptacle to operate with said suction head and said suction generator; and wherein latching mechanisms are formed on corresponding upper and lower axial ends of said dust filter and said filter receptacle to facilitate releasable latching between said dust filter and said filter receptacle to facilitate said plug-in coupling. 
     
     
       14. A vacuum cleaner according to  claim 13 , wherein a dusted inlet channel connects between said suction head and said dust filter, and said dusted air inlet channel extends from said suction head to beyond said dust filter and returns towards said dust filter for air coupling therewith. 
     
     
       15. A vacuum cleaner according to  claim 11 , wherein the peripheral wall has a concavely curved profile to define a secondary reservoir having a concave base. 
     
     
       16. A vacuum cleaner according to  claim 11 , further comprising a secondary dust filter which is downstream of said dust filter, wherein said secondary dust filter is a dry filter, such as a pleated element type filter or a multi-stage filter. 
     
     
       17. A vacuum cleaner according to  claim 16 , wherein said vacuum cleaner is a stick-like or broom-like shaped vacuum cleaner. 
     
     
       18. A vacuum cleaner according to  claim 17 , wherein said suction generator is mounted on said rigid and elongate housing portion and above said filter receptacle.